clear, close, clc

d = 5;
k = 4;
s = tf('s');
sys = 1/(s^2+5*s+4);
% step(sys)

d = 1;
for k=.1:.1:2
    sys = 1/(s^2+d*s+k);
    bode(sys)
    pause(0.1)
    hold on
end